Sponsor
Portland State University. Department of Biology
First Advisor
Randy Zelick
Term of Graduation
Spring 1995
Date of Publication
5-17-1995
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Biology
Department
Biology
Language
English
Subjects
Ototoxic agents, Auditory pathways -- Effect of drugs on, Vestibular apparatus -- Effect of drugs on, Amphibians, Anura
DOI
10.15760/etd.6734
Physical Description
1 online resource (2, 75 pages)
Abstract
Hair cell trauma from aminoglycosides, which may lead to permanent loss of hair cells in mammals, was studied physiologically in frogs by measuring an auditory evoked potential (AEP) in Rana pipiens. The AEP was evaluated in order to measure threshold shift (TS) and recovery from TS after the administration of the aminoglycoside antibiotic, gentamicin. To obtain an AEP, chronic electrodes were implanted into the cranium near the cochlear nucleus. The frogs were then exposed to frequency-specific narrow band "clicks" which included a single period 1 kHz sinewave, and a computer synthesized high frequency and low frequency click. Amphibians have two hearing organs, the amphibian and basilar papillae, sensitive to low (150-1500) and high (1500-2000) frequencies, respectively. The low (AP) and high (BP) frequency clicks were created to stimulate specifically the corresponding papillae. After normal thresholds were recorded for each frog, gentamicin sulfate, 200 μM, 300 μM, or 400 μM, was injected bilaterally into the otic capsules. Thresholds were recorded until the TS had disappeared, allowing the threshold recovery period to be measured. The injections of 200 μM yielded a 10 dB change in one animal and no change in two others. The injection of 300 μM into 10 frogs and 400 μM into 20 frogs yielded at least a 10 dB change in 60% and 93% of the frogs, respectively, with the concentration of 400 μM producing threshold shifts of 20 dB. Thus, the threshold shifts were dose-dependent. Recovery times varied between six and fourteen days. No apparent differences between thresholds for the high frequency click, low frequency click and sinewave clicks were observed.
Rights
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Persistent Identifier
https://archives.pdx.edu/ds/psu/28366
Recommended Citation
Brown, Michael Patrick, "Effect of Ototoxic Drugs on the Amphibian Auditory System: Injection of Gentamicin Sulfate into Anuran Otic Capsules and Recovery of Thresholds" (1995). Dissertations and Theses. Paper 4858.
https://doi.org/10.15760/etd.6734
Comments
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